Electric cars are quieter, do not pollute (if they use renewable energy), and can be one of the key components of sustainable mobility when moving away from fossil fuels. However, they are not without their own challenges: from the raw materials required for batteries to charging speed, there are uncertainties that need to be resolved on their path to mass adoption. Fortunately, technological advancements are offering solutions, whether through battery alternatives or fast charging systems, improving the efficiency of electric cars. More details about fast charging for electric cars will be discussed in this article. Has NASA discovered the key to fast charging for electric cars?
Key points covered in this article:
How long does it take to charge an electric car?
For over a century, internal combustion engines have been dominant due to their high range and quick refueling. Filling up a gasoline tank usually takes two or three minutes, unless there is a line at the gas station. On the other hand, charging an electric vehicle (EV) can take anywhere between twenty minutes and twelve hours to fully charge. Several factors influence these charging times.
- Type of charging point: Charging points come in different types based on their power level, ranging from 1 to 3. Domestic charging points are typically type 1, while more powerful types 2 and 3 are found in public places.
- Battery type and capacity: Battery capacity varies from 6 kWh for city cars to 100 kWh for long-range models, with the average usually falling between 40 and 50 kWh.
- Charge level: Charging the initial and final 20% of the battery takes the longest time.
- Ambient temperature: Charging speed decreases in very low temperatures.
Interestingly, NASA has incorporated extreme cooling into their prototype in collaboration with Purdue University to take advantage of this last point.
How to speed up fast charging for an electric car
Increasing charging power faces a physical obstacle, similar to a stove or hairdryer operation, where electricity passing through a resistance emits thermal radiation. The thick “hose” of fast charging points contains numerous braided cables to prevent overloading and usually includes a cooling liquid. These charging points typically deliver a power of 350 amperes.
NASA’s new system can amplify the electric current carried by the power cables of an electric charging station by 4.6 times, functioning smoothly at 1400 amperes, technically capable of reaching 2500 amperes. They have implemented a temperature control system designed for operation under microgravity conditions in outer space to achieve this. The underlying physical principle is known as subcooled flow boiling, dissipating up to 24.22 kilowatts of heat through this technology.
The prototype was developed by Purdue University, applying NASA’s research on subcooled flow boiling to the realm of fast charging for electric cars. The university’s laboratory even announced another fast-charging technology below five minutes by 2022.
How does subcooled flow boiling work?
Subcooled flow boiling occurs when a liquid is rapidly heated and starts to boil before reaching its average boiling temperature. For instance, placing a pot of cold water on a ceramic hob or gas stove gradually heats the water until vapor bubbles form, even before the entire liquid reaches its boiling point, dissipating heat with them as they detach from the surface.
Subcooled flow takes place when a moving liquid, like water flowing through a pipe, is cooled below its standard boiling temperature before boiling. This occurs when there is a swift transfer of heat to the liquid or when the liquid is under high-pressure conditions.
Initially intended for space missions and Mars colonization, this technology requires all elements – from the battery to the charging station and power cable – to be prepared for that level of power. The potential for this technology to be employed in fast charging for electric cars on Earth, contributing to a more sustainable economy, remains to be seen.
Source:
